Underwater kite



d Q r" Jan. 21, 1947. F, oRRlLL 2,414,48o

UNDERWATER KITE Filed Feb. 7, 1945 4 SheO ts-Sheec l F. 60/?00/V MORE/Al WMMW Jan. 21, 1947. F. e. MORRILL UNDERWATER KI'fE Filed Feb. 7, 1945 4 Sheets-Sheet 2 E 60200 Make/a Jan. 21, 1947.

F. G. MORRILL UNDERWATER KITE Filed Feb. '7, 1945 4 Sheets-Sheet 3 grwe/wtoz E 60/200 Mame/.44

Jan. 21, 1947. F. G. MORRILL 2,414,480

UNDERWATER KITE Filed Feb. 7, 1945 4 Sheets-Sheet 4 awe/whom 5 602.00 MOP/Wad Patented Jan. 21, 1947 UNITED STATES ATENT OFFICE UNDERWATER KITE Ferdinand Gordon Morril l, New York, N. Y.

Application February 7, 1945, Serial No. 576,681 11 Claims.- (o1.114 235) (Granted under the act of" amended April 30, 1928;

This invention relates to devices for maintaining underwater tow lines at given positions'with respect to the towing ship, and more specifica ly, to paravane for use with mine laying and sweeps equ pment, and the method of manufacturing the same.

- In many instances, and in particular in mine laying and sweeping, tow lines are employed which must be maintained at a given depth at the opposite sides of the ship or astern thereof. Heretofore, paravanes have been employed to hold the tow lines at the desired position with respect to the ship, but the harness for attaching the paravane to the tow lines and necessary to the adjustment of the paravane so that it would maintain the selected position, has given a great deal of trouble, both as to its initial adjustment and as to maintenance of its adjustment after the paravane was submerged.

It is an obiect ofthis invention to provide a paravane so designed that no harness is necessary and. of such surface contour that it automatically will maintain itself at a given position with respect to the ship for any speed of the towing ship.

To this end, invention in one aspect resides in a paravane consisting of two corresponding substantially triangular elements joined together along a pair of corresponding sides to form a dihedral angle between their plane surfaces and with the corresponding sides at the opposite ends of the joined sides converging to form the leading and the trailing edges of the paravane. As illustrated, the cross section of each element is in the form or a reverse camber airfoil, and as arranged, the plane of the sides of each of the elements which form the leading edge are normal to the trailing edgethereof. There is also included a tow member adapted for single point attachment to a tow line andso situated with respect to the paravane, that the paravane will move in a horizontal plane, regardless of the pull applied thereto. I o

It is another object of this invention to provide am'ethod for manufacturing paravanes of the aforesaid characteristics.

As illustrated, the method consists in providing a length of structural material with parallel edges having a cross section corresponding in shape to a reverse camber airfoil, making a pair of'parallel spaced transverse cuts across the structural member, making a pair of angular cuts across the member extending from one end of the first pair of cuts in adirection to intersect substantially midway between the parallel cuts thereby to'fornr March 3, 1883, as 370 o. G. 757) a pair 'of similar right triangular elements, discarding the triangular piece between the angular cuts, and bringing the'triangular element thus formed, together, hypotenuse to hypotenuse. In joining the aforesaid elements, the method includes forming dovetail cavities in the elements near their joined edges, applying a thermosetting cement'to the edge and cavities, subjecting theelements to pressure, inserting double dovetail blocks in the cavities and heating the assembled elements suificiently-to activate and set the thermoplastic cement.

The invention will now be described with reference to the accompanying drawings, in which:

Fig. 1 is a plan view of the improved paravane constructed in accordance with my invention;

Fig. 2 is a side elevation of my improved paravane howing an edge and the upper surface on the near side thereof;

Fig. 3 is an end view as seen from the front end of the paravane;

Fig. 4 is a diagrammatic layout of the contour of the preferredcross section employed in the paravane;

Fig. 5 is a perspective view of a tow member for the paravane;

Fig. 6 is a cross section of the structural member before it is shaped as in Fig. '7, showing the laminated construction thereof; 7

Fig. 7 is an end view of the structural material showing the preferred cross section thereof;

Fig.3 is a plan view of a short length of the structural material fromwhich the paravaneis, made showing the lines along which the material is'cut to provide the component parts of the paravane; and

Fig. 9 is an elevation of the front edge of the structural material shown in Fig. 8.

Referring to Fig. l; the paravane i0 is generally convex-concave as viewed from the top, and flares from its point H rearwardly. As illustrated, it consists of a pair of right triangular elements If. and I4,

enuse {l6 and l8 to provide a. substantiallyflkite shaped device, the elements l2 and l lbeing held joined along their hypot:

inserted in place and the elements are subjected to pressure while heat is applied to activate the thermo setting cement. As thus made up, the corresponding sides 28-28, Fig. 1, of the two substantially triangular elements It and I4 converge to form the leading edge of the paravane, and the corresponding sides 3lJ--30 converge to form the trailing edge of the paravane. The sides 28 and 31] of each element intersect substantially at right angles. The plane of the hypotenuse edges i6 and E8 of each of the elements lie at an angle of substantially 60 with a medial plane passing through the element so that when these elements are joined in the manner described, they will form a dihedral angle D, as represented in Fig. 3. The dihedral angle shown is 120, however, it is within the scope of the invention to modify the size of the dihedral angle. The corresponding sides 28-28 of each of the elements l2 and M is in cross section in the shape of a reverse camber airfoil as shown in Fig. 'I.

The plane of each of the sides 28-28 is substantially normal to the medial line of the cross section and constitute, as heretofore pointed out,

the leading edges of the paravane. As illustrated,

the plane of the sides 28--28 slope from the top of the paravane downwardly and inwardly toward the under concave side. The trailing edge 30-40 is formed by the meeting of the upper and lower surfaces of the elements, that is, is constituted by the thin edge of the structural member from which the paravane is constructed.

The shape and distribution of the weight of the paravane as described above, is such that the sum of forces acting on the paravane at any 5 speed of the towing ship and for a given weight of the paravane itself is zero, that is, the paravane will maintain a given depth at any speed and will move without swinging from one side to the other and in a horizontal plane without rotation about any point within or without itself.

In order to tow the paravane, as thus constituted, there is included a tow member 32 which consists of a flat plate disposed in a vertical position so that it projects upwardly from the upper surface of the paravane, the plate having laterally projecting arms 34 adapted to occupy recesses 38 formed in the hypotenuse edges of the elements l2 and M and to be fixed therein when the elements 12 and M are assembled, as described above.

In manufacturing the aforesaid paravane, there is provided a prefabricated structural member 38 having parallel edges which may be made up in any suitable length, convenient for handling. While the member 31 may be made up of any desired material, for example, sheet metal, cast metal, composition or plastic, it is shown herein as being composed of laminations of wood as indicated in Fig. 6. In order to provide for the proper weight distribution, the lamina 38 are so designed and are made of such material that the specific gravity of the section of the member which is to form the rear part of the" paravane, is approximately .30, while the lamina 40 which make up that portion which is to constitute the forward portion of the paravane, are composed of the material whose specific gravity is 1.3 or greater. With such a prefabricated structural member, the process of making up thecomponent parts of the paravane consists of -making a pair of spaced parallel cuts 42 transversely of the structural member, as shown in Fig. 8, and a pair of angular cuts 44 extending from the thick edge of the structural member toward the thin edge, and converging so that they intersect substantially at the mid point between the parallel cuts 42. This, it will be observed, forms the two triangular elements l2 and I4 and an element 46 which may be discarded. The plane of the angular cuts 44-44 are made at an angle of substantially 30 with a plane normal to the surface of the structural member 31, as seen by reference to Fig. 9, so that when the elements I2 and [4 are joined, the aforesaid dihedral angle D of will be established.

The elements l2 and M are joined by cutting dovetail cavities in their upper surfaces adjacent to their hypotenuse edges and placing the elements together, hypotenuse to hypotenuse, after having applied a thermo setting cement on their edges, applying pressure to the elements and driving the double dovetail blocks 2ll--'22 into the cavities. At the same time there is included the tow member 32 which sets in between the elements in a cavity provided therefor, the lower end of the member. having laterally extending arms 34 adapted to extend into recesses 36 formed in the hypotenuse edges arranged to accommodate the arms.

The nature of the cross section, which as heretofore has been described as a reverse camber airfoil, is important in that it is the airfoil surface and distribution of the weight in a member of such a cross section that causes the paravane, when submerged at a given depth, to travel in a horizontal plane at the aforesaid depth, the depth not depending upon the speed with which the paravane is being pulled through the water. This cross section is common to that used in airplane construction and is acted upon in the water in the same manner that a wing of corresponding cross section would be acted upon by the air if moving throughthe air. The contour of the reverse camber airfoil in relation to its center plane of control, and center plane'of wing and its proportions, is shown in Fig. 4, and with this design, it is possible to attach a tow line 'to the member 32 at a single point and draw the paravane through the water without any tendency for it to tip about its point of rotation in one direction or the other, or for it to move from one side to the other with respect to the line of tow.

In certain instances, it may be desirable to weight the paravane and this may be done by forming cavities in the paravane at any desired point and filling the aforesaid cavity with lead or other weighting material. The weighting may be done in the tail or in the nose or in any other portion of the body of the paravane which will give the desired characteristic to the paravane.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is: v

1. A method for making a paravane comprising cutting from a length of structural material having a cross section corresponding in shape to a reverse camber airfoil, a pair of similar right triangular elements in such a manner that one side of each triangular element corresponds to said cross section of said structural material and joining said elements along their hypotenuse.

2. A method for making a paravane comprising cutting from a length of structural material having a cross section corresponding to the shape of a reverse camber airfoil, a pair of similar right triangular elements in such a manner that one side of each element corresponds to said cross section of said structural material and the hypotenuse edge is undercut, and joining the undercut hypotenuse sides to form a dihedral angle between the planes of said elements.

3. A method for making a paravane comprising cutting from a length of structural material having a cross section corresponding in shape to a reverse camber airfoil, a pair of right triangular elements in such a manner that one side of each triangular element corresponds to said cross section of said structural material, joining said elements along their hypotenuses, and fixing a tow member between said sections.

4. A method for making a paravane, comprising cutting from a length of structural material having a cross section corresponding in shape to a reverse camber airfoil, a pair of right triangular elements in such a manner that one side of each triangular element corresponds to the cross section or said structural material, forming dovetail cavities in said elements adjacent to their hypotenuse sides, applying an adhesive to said side and cavities, inserting double dovetail blocks in said cavities while applying pressure to said elements to press said hypotenuse sides together and subjecting the assembled elements to heat to activate the adhesive.

5. A paravane comprising two right triangular members joined together, hypotenuse to hypotenuse, so that one set of converging sides of said members constitutes the leading edge and the other set of converging sides constitutes the trailin edge of the paravane, the sides constituting the leading edge corresponding in shape to the normal cross-section of a, reverse camber air foil and the surface of each member being such that every element thereof is a straight line normal to the plane of its leading edge and intersecting the periphery of the side forming its leading edge.

6. A paravane comprising two triangular members having corresponding sides joined together so that the correspondin sides at opposite ends of the joined sides converge to form a, leading edge and a. trailing edge, said members having sides and surfaces so constructed that each side of the converging sides forming the leading edge has a shape corresponding to the normal crosssection of a reverse camber air foil and lies in a plane normal to one of the sides formin the trailing edge and that each surface is such as would be generated by an element normal to one of the sides forming the leading edge and moving peripherally thereof.

'7. A paravane comprising a pair of right triangular members joined along their hypotenuses to form a dihedral angle between said members with the corresponding sides at opposite ends of the joined hypotenuse forming the leading and trailing edges of the paravane, the side of each member which constitutes one of the sides of the leading edge corresponding in shape to the normal cross-sections of a reverse camber air foil and the surface of each member being such that every element thereof is a straight line perpendicular to the plane of said side.

8. A paravane comprising two right triangular members, means for joining said members hypotenuse to hypotenuse so that one set of converging sides of said members constitutes the leading edge and the other set of converging sides constitutes the trailing edge of the paravane, the sides constituting the leading edge corresponding in shape to the normal cross-section of a reverse camber air foil and the surface of each member being such that every element thereof is a straight line normal to the plane of its leading edge and intersecting the periphery of the side forming its leading edge, and mean interposed between said members for attaching a tow line.

9. A paravane comprising two right triangular members adapted to be joined together hypotenuse to hypotenuse so that one set of converging sides of said member constitutes the leading edge and the other set of converging sides constitutes the trailing edge of the paravane, the sides constituting the leading edge corresponding in shape to the normal cross-section of a, reverse camber air foil and the surface of each member being such that every element thereof is a, traight line normal to the plane of its leading edge, corresponding recesses in the hypotenuse sides of said members, and means cooperable with said recesses to lock said members together.

10. A paravane comprising two right triangular members adapted to be joined together hypotenuse to hypotenuse so that one set of converging sides of said members constitutes the leading edge and the other set of converging sides constitutes the trailing edge of the paravane, the sides constituting the leading edge corresponding in shape to the normal cross-section of a reverse camber air foil and the surface of each member being such that every element thereof is a straight line normal to the plane of its leading edge, corresponding dovetailed recesses in the hypotenuse sides of said members, and double dovetailed blocks cooperable with said recesses to lock said members together.

11. A paravane comprising two right triangular members joined together hypotenuse to hypotenuse, so that one set of converging sides of said members constitutes the leading edge and the other set of converging sides constitutes the trailing edge of the paravane, the sides constituting the leading edge corresponding in shape to the normal cross-section of a reverse camber air foil and the surface of each member being such that every element thereof is a straight line normal to the plane of its leading edge,and means associated with said members for attaching a tow line.

FERDINAND GORDON MORRILL. 

